Treatment of hydrocarbons



Patented July 23, l946 TREATMENT OF HrDItooARBo s Louis Schmerling andVladimir N. Ipatiefl, Chi- ,cago, IlL, assignors to Universal OilProducts Company,

I ware v Chicago,,Ill., a corporation of Dela- No Drawing. Ap'DlicatiohJuly 6; 1942,

Y Serial No. 449,946

'16 claims. (01. 260-15834) This invention relates to the treatment ofiso v paraffinichydrocarbons to produce therefrom:

, branched chainparaflinic hydrocarbons-oi higher molecular weight; 1 Ina'more'specific sense, th-is invention'is concernedwithsaznovelproc'esskfor interacting alkylatable paraflinichydrocarbons,

herein termed isopai'affini'cuhydrocarbons, with alkyl esters ofchloroformicacidto produce higher boiling'parafiihic hydrocarbons ofgasoline boiling range.

In one specific embodiment, the present invention relates to a processfor synthesizing hydrocarbons which comprises reacting an isoparafiinichydrocarbon with an alkyl chloroformate under alkylating conditions inthe presence of a Friedel-Crafts type metal halide catalyst.

Considerable'quantities of butanes, pentanes, and other paraifinic'hydrocarbons of relatively low molecular Weights are available in therelatively light hydrocarbon material condensable from natural gas andusually referred to as casing head gasoline. These relativelylightcomponents of casing head gasoline also includevcertain amounts of thecorresponding isoparafiins, namely, isobutane, isopentane, etc. Therelatively low boiling normal paraflins may also be isomerized into thecorresponding isoparaffins by suitable treatment. Furtherquantitiesofjbutanes and pentanes are formed as by-products'in thecracking of petroleum fractions and of other hydrocarbon oils toproducegasoline.

Alkyl esters of chloroformic acidhwhic'h are utilizable as alkylatingagents in the process of the present invention have the general formula:ClCOOR, in which R represents'an alkyl group. Alkyl chloroiormates arereadily obtainable by the treatment of an alcohol with phosgene, Thus,as indicated in the following equation, reaction of 1 molecule ofphosgefne with 1 molecul e of iso pro'pyl alcohol results in .the'formation oi 1 ,molecule each of isop-ropyl chloroformate andehyd'rogenchloride: H i v 03H10H +0001, 0100065111 l am V the respective boilingpoints'which are listed as" follo'w's:--* 1 :3: :wi'

Friedel-Crafts type metal halides which are; I utilizable as catalystsfor promotingthe alkyla tion of an isoparaffin with an alkyl chlorofor=matein accbrdance with thepresentinvention in-I s c1ude;suchjsaltfs asaluminum chloride;aluminum bromide, zi chloride, ant-i lyst insuchalkylation' reactions because ;it

reaction under specified conditions.

methane. Other Friedel-Crafts-type metal halides andparticularlychlorides may be added ,to

the aluminum chloride or to its'solution ior thepurpose, of modifyingthe, activity of the num chloride.-

iWhile amy audn r isopara ili nic by alkyl chloroformates vmayibe.efie'cted in. the.

' presence oflaluminumchloride andother Fried Crafts type catalysts. attemperature 0 1mm about gzo to. about-1 peraturepf from about-10 1 ingrange with relatively srnall amounts of jun- Isopropyl Phos- IsopropylHydrov alcohol gene chloroformate gen ride Some of the alkylchloroformates which are often referred to as alkyl 'chlorocarbonateshave desira'bleside reactions, such as polymerization,

formation of organic compounds I containing Q chlorine, etc, it isdesirable t maintain a molar excess of isoparailin hydrocarbon-to alkylchloromm? ,pressure chloride, zirconium chloride, ferric m m ch de. i muflp l r and others; We prefer, however, to employ alu-j minum chlorideasthe Friedel craifts type; cata" V ,c, ne u' elr Meme. to about 7Q? C, ispreferred; Pressuresutilizable inlthe'process may varyfrom'substantiallyatmospheric to about 50.. atmospheres or more. Inorder to obtainwhighyields of hydrocarbon products of gasoline boilformate throughout theentire reaction period. Generally from about 2 to 25 molecularproportions of ,isoparafiinic hydrocarbons should be present permolecular proportion of alkyl chloroformate introduced to an alkylationreaction mixture in order to form a substantially saturated hydrocarbonmaterial and to avoid undesirable polymerization and decompositionreactions. v

The reactions which occur during the treat ment of an isoparaflinichydrocarbon with an alkyl chloroformate in the presence of a Friedel-fCrafts type metal halide, or m ture of said metal halides, apparentlyinvolve the combination of the isobutane with the ester of chloroformicacid accompanied by splitting out of'carbon; dioxide and hydrogenchloride as illustrated by the following equation: e

A101: iC4Hm C1C0OQ3H7 C1Hm 002 1101 Isobu- Isopropyl Hep- Oar- -Hyd.ro-V tane chloroformate tane .bon lien; diox ch: g

' ide ride 1' V The us'eof chloroformates (or chlorocarbonates as theyare often called) :has the advantage over i the similar us of otheresters in that no :iree

viding a mixing zone through which the reacting organic compounds andcatalyst are passed un der alkylating conditions and in which sumcienttime is given for the completion of the desired isoparafiin alkylation.-The products from such;

a reaction zone are then directed to a separating zone inwhich thealkylationproducts are separatedfrom. the unconverted iso'paraifinichydrocarbon, catalyst, and amixture of hydrogen chloride and carbondioxide. The recovered unconverted isoparafiinic hydrocarbonand catalystare then recycled to contact with the mixture of 150'- I parafi'lnichydrocarbon and alkyl chloroformate being charged to the process.Hydrogen chloride may also be recycled if desired.

, The activity of the Friedel-Crafts type catalyst employed in theprocess is dependent upon the w particular metal-"halide ormetal halidemixture so utilized.

, to catalyze the alkylation are not necessarily equivalent in theiraction particularly when react ing differentisoparaffins with variousalkylchloorganic acid'is produced during such reaction.

' Acco'rdingly,-the aluminum chloride used as 'cata-- lyst in theprocess does not 'form an aluminum chloride-organic acid complex, andhence only catalytic and not stoichiometric amounts of aluminumchlorideare'necessary for the reaction;

Although'the mechanismsof the reactionslin volved are not understoodcompletely and should not be construed to limit the scope of the 'inyenftion, the interaction, for example, of'isobutanez,

with isopropyl chloroformate yields heptanes. which include2,2,3-trimethylbutane, generally.

known as triptane. Heptanes so formed may react rurther with anadditional quantity ofthe alkyl chloroformate such as isopropyl chloro--forrnate to form a parafiin hydrocarbon of still higher molecular weightsuch as -a decane. Dec-I anes'and other hydrocarbons :of relatively highmolecular weight may undergo decomposition and further conversionreactions in the presence of the catalyst to produce'lowenand higherboiling hydrocarbons which are generally paraffinic in naturelg Theprocess of the present invention may be 7 carried 'out either in batchor continuous types of operation. In batch type operation, the preferredprocedureis .to, agitate a mixture of paraflinic hydrocarbon andcatalyst at the chosen operating temperature and pressureand'tointroduce gradually thereto an alkyl chloroformate or a.

mixture comprising essentially an alkyl chlorov formats andanisoparafiinic hydrocarbon or. an

of 'mixing suflicient to effect substantially complete reactionofthealkyl chloroformat'e withisoparaffinicjhydrocarbon fraction; After atime the isoparafiimthe isopalis flin being present ;in.

excess oftli'ea1kyl chloroformateat all times, the

agitation islstojpped and the reaction mixture is separated into usedcatalyst, unconverted isoparaiiin; alkylation product, and a mixture ofhydrogen chloride an'd carbon dioxide, the latter two materials kresulting from the decomposition of the alkylfchloroformate. Therecovered catacovered from a previous alkylation run.,.

'T-heprocess may be made continuous by proe chloroformate 1 Run numberReactants, g.: 7 r Ethyl chloroiormate. 110 110 110 Isobutane 172 168 81V 172 Aluminum chloride 40 40 :20 .40 Autoclave lining Nickel GlassNickel Pressure, atm.:

Initial, nitrogen added- 2 1 4 30 7 Maximum 4 1B ,50 25 Final at 20 O 1018 43 17 Temperature, C 7 40 1 50 Duration of run, hours 5 6 4 7.Products, g.: V

Gondensible'gas 173 70. 152 Liquid hydrocarbon layer 0 27 15 66 Catalystlayer 43 54 28 45 Hydrogen chloride, carbon dioxide, and lcss. 64 38 59'Distn. of hydrocarbon layer,. volume percent: a i Condensible gas -V 3f;(52

Liquid-fractions:

. Below 40 C V 12 8 Between 40 and 75 0-. 30 37 22 Between 75 and 95 0...7 7 4 Residue 9 9 Analysis of .condensable gas, mole percent: r r IEthane .5. 8 Propane 1. 6 -2. Butane--- -77.5 79.6 ;2 79. Ethyl chloride21.6 16.6 10. Pentane and higher hydr i i bons i 0.9 3. 8 1 12. 4 8

The different Friedel-Crafts type metal halide mixtures which may beemployed roformates' having alkyl,1groups of increasing carbon chainlength and'degree of branching.

The following examples are given to illustrate the characterof'theresults obtained by, the use l l of the. present process,although, the "data present'd' are not introduced with the intention ofi the generally broad scope "of the E unduly limiting invention. V

" r EXAMPLEI 'Alkylation of isobutane by ethyl chloroformate was carriedout by charging to a rotatable auto;

clave (lined with glass or nickel) a mixture; oi the 'isobutan'e; ethylchloroformate, and catalyst in the amounts indicatedi n Table I.

Table I. m1/zationlo isobutane with-ethyl "The results given in Table ishow that alkylation' occurred in good yields at temperature of 40 C. orhigher. It is interesting tonote that 44.8; ethyl chloride, 25.4;pentane and higher the liquidpro'duct boiled at; a relatively low rem-'perature and most'of' it boiled between40- and 75 C. with very littleboilingabove' 100 C. a 1

EXAMPLE II A total of' 120 grams'of isopropylchlorofor'mate was addedslowly to 'a glassareactor"containing a and 20' grams of aluminumchloride. The reaction temperature was maintainedataboutfthe boilingpoint of isobutane"under=l fatmosphere pressure by permitting theisobutane to-reflux:

under a well cooled condenser while. the isopropyl chloroformate was"introduced ."graduall'y't'o the reaction mixture 'over a periodof3hours.

Hydrogen chloride was evolved at aimoderate orless liquid hydrocarbonmaterial and 42 grams of used catalyst having the appearance of areddish brown oil. In addition to the liquid hydrocarbons and catalyst,the recovered materials comprised 148 grams of condensible gases(chiefly isobutane) and 41 grams of a mixture of hydrogen chloride andcarbon dioxide. The relatively large loss of 62 grams was probably dueto a mechanical loss of hydrogen chloride and carbon dioxide. Thecondensible gas consisted of 28.5 mole per cent of propane, 67.2% ofbutane, and 4.3% of pentanes. The 52 grams of colorless liquidhydrocarbon material recovered in this run represent 125% by weight ofthe propylene which may be considered available from the isopropylchloroformate. Distillation separated the liquid product into fractionshaving the boiling ranges and refractive indexes indicated in Table 2.

- well stirred mixture of 205 grams of isobutan'e- 1 which comprisesreacting an iso'paraffinic' hydro- 'we-aaim js ourfiinventionz;

1. A "process for;"s'ynthesi'zirig ydrocarbons r v which comprises'reactingan iso'paiafl'lnic'*lji'ydr63- carbo'njwitha-n alkylcliloroforniate uhder alkyl- CIfaftstype inetal halide catalyst. I

, 2, AQ process fonsynthesizing hydrocarbons which comprises: reacting:an isoparaffinic hydro carbon with an alkyl chloroformate at 'a temper-*ature of from about to about 100 C. in the presence fof a at l -Y 3. Aprocess for synthesizing hydrocarbons Friedel Crafts type metal "halidecarbonwithan alkyl chloroiorrnalte' at a tempera ture of 'from about '20to-about- 100" C. under a pressure of, from substantially atmospheric toabout 150 atmospheres in the presence of a Friedel Craits type metalhalide catalyst.

The increased Crafts metal halide catalyst, whilev main-' tainingfamolarexcess of said isoparafilnic hydr carbon' to said alkylchloroformate throughout the entire reaction period. 1

5. A process for synthesizing. hydrocarbons 4. A process forsynthesizing hydrocarbons which comprises reacting an iso'parafilnichydro ca'rbon' with an alkyl chloroformate under-jalk'yl:

ating'conditions in the 'presencefot'a Fr iedel which comprises reactingan isoparafl'inic hydrocar bon with an alkyl chloroformate at atemperature of from about 20 C. to about 100 C. under a pressure of fromsubstantially atmospheric to about 50 atmospheres in the presence of aFriedel-Crafts type metal halide catalyst while maintaining a molarexcess of said isoparaflinic hydrocarbon to said alkyl chloroformatethroughout the entire reaction period.

6. A process for synthesizing hydrocarbons wh ch comprises reacting anisoparafiinic hydrocarbon with an alkyl chloroformate under alkylatingconditions in' the presence of an aluminum Table 2.--Distillation ofnormally liquid hydrocarbon product formed by reactionnf isobutane withisopropyl chloroformate in the presence of aluminum chloride [Charge: 69cc. (48.7 g.)]

Vol. of traction, cc.

Boiling Fraction No. rgndge, index Refractive halide catalyst 7. Aprocess for synthesizing hydrocarbons which comprises reacting anisoparaflinic hydrocarbon with an alkyl chloroformate under alkylatingconditions in the presence of an aluminum chloride catalystwhilemaintaining a molar excess of said isoparaffinic hydrocarbon tosaid alkyl chloroformate throughout the entire reaction period.

8. A process for synthesizing hydrocarbons which comprises reacting anisoparafiinic hydrocarbon with an alkyl chloroformate at a temperatureof from about 20 to about C. in the presence of an aluminum chloridecatalyst while maintaining a molar excess of said isoparaffinichydrocarbon to said alkyl chloroformate throughout the entire reactionperiod.

9. A process for synthesizing hydrocarbons which comprises reacting anisoparaffinic hydrocarbon with an alkyl chloroformate at a temperatureof from about --20 to about 100 C. under a pressure of fromsubstantially atmospheric to about 50 atmospheres in the presence "of analuminum chloride catalyst while maintaining a molar excess of saidisoparaflinic hydrocarbon to said alkyl chloroformate throughized inthat said isoparaffinic hydrocarbon com-' prises isopentane.

12. A process for synthesizing hydrocarbons aftingjconditions in thepresence of a lfriedelq 7? I which comprises reacting an isoparaflinichydrocarbon with an alkyl ohloroformate at a temperature of from about20j toabout 10p-,C.

under'a pressure of from substantially atmos-v pheric to about 50atmospheres in the presence of aluminum chloride and'another Frie del-Crafts type catalyst while maintaining a molar excess of-saidisoparafiinic hydrocarbon to said alkyl chloroformate throughout .the'entire reaction peri'od.- .7 1

13, A process for synthesizing hydrocarbons which comprises reacting anisoparaffinic hydro: carbon with an alkyl chloroformate ata ,temperatureof from about to about 100910.

undera; pressure of from substantially atmlo'se.

pheric to about 50 atmospheres in the presence ofa composite comprisingessentially, aluminum from substantially atmospheric-to'about50 at:mospheres in the presence-of an aluminum "chloride catalyst. whilemaintaining, a molar excess;

of said isobutane to said ethyl 'chloroforrnate throughout the entirereaction period.

15.-A process forsynthesizing hydrocarbons of gasoline boiling rangeand-high antiknockrvalue whichcomprises contacting onemoleculanproportion of ethyl chloroformate and from about 2',

to about molecular proportions of isobutane with an aluminum chloridecatalyst at a semiperature of fromr about toabout 100 C.

atmosunder --a pressure of *from substantially pheric to' aboutatmospheres.= 1

. '16." A process for synthesizing hydrocarbons of gasoline boilingrange and high antiknock value chloride anda refractory carrier whilemaintain-.

ing a molar excess ofsaid isoparaflinichydroe, carbon to said alkylchloroformate I throughout the entire reaction period,

;14;;A process for'synthesizing hydrocarbons of gasoline boiling rangeand high antiknock comprises reacting isobutane with value which I Vethyltchloroformate at a temperature of, from "about' io to about 1009C. under a pressureof which comprises contacting one molecular pro-'portion of a propyl chloroformate -and from'about:

' 2 to about 26 molecular proportions of isobutane "perature of fromabout 20"-to about C.

with'an aluminum chloride catalyst at a temunder a pressure of fromsubstantiallyatmosw pheric to about 50'atmospheres.

LOUIS SCHMERLING; VLADIMIR N. IPA'IIEER,"

